Intense 8-fs pulse generation in the deep ultraviolet

By use of the recently developed technique of guided-wave frequency conversion, the generation of sub-10-fs light pulses in the UV has been demonstrated for what is believed to be the first time. Cross-phase modulation of the light in a hollow waveguide produced a bandwidth of 16 nm, with a center frequency of 270 nm, at 1 kHz. A simple grating pair was used to compress the pulses to a duration of 8 fs, as measured by self-diffraction frequency-resolved optical gating. In the experiment the compressed energy was greater than $1 \mu \mathrm{J}$, with a peak power of $>100 \mathrm{MW}$; the technique can be scaled to higher energy. Further improvements should make it possible to generate pulses as short as $\sim 3 \mathrm{fs}$ with this technique.